Khan Academy Practice

Video Tutorial:
https://www.khanacademy.org/math/algebra-home/alg-linear-eq-func/alg-solutions-to-two-var-linear-equations/v/ordered-pair-solutions-of-equations

The substitution method for solving linear systems

http://www.mathplanet.com/education/algebra-1/systems-of-linear-equations-and-inequalities/the-substitution-method-for-solving-linear-systems

11-16
2.4.
Read P. 40
Practice P.41 2.4A
P.42 2.4 D and E